// filehdr.cc 
//	Routines for managing the disk file header (in UNIX, this
//	would be called the i-node).
//
//	The file header is used to locate where on disk the 
//	file's data is stored.  We implement this as a fixed size
//	table of pointers -- each entry in the table points to the 
//	disk sector containing that portion of the file data
//	(in other words, there are no indirect or doubly indirect 
//	blocks). The table size is chosen so that the file header
//	will be just big enough to fit in one disk sector, 
//
//      Unlike in a real system, we do not keep track of file permissions, 
//	ownership, last modification date, etc., in the file header. 
//
//	A file header can be initialized in two ways:
//	   for a new file, by modifying the in-memory data structure
//	     to point to the newly allocated data blocks
//	   for a file already on disk, by reading the file header from disk
//
// Copyright (c) 1992-1993 The Regents of the University of California.
// All rights reserved.  See copyright.h for copyright notice and limitation 
// of liability and disclaimer of warranty provisions.

#include "copyright.h"

#include "system.h"
#include "filehdr.h"

//----------------------------------------------------------------------
// FileHeader::Allocate
// 	Initialize a fresh file header for a newly created file.
//	Allocate data blocks for the file out of the map of free disk blocks.
//	Return FALSE if there are not enough free blocks to accomodate
//	the new file.
//
//	"freeMap" is the bit map of free disk sectors
//	"fileSize" is the bit map of free disk sectors
//----------------------------------------------------------------------

bool
FileHeader::Allocate(BitMap *freeMap, int fileSize)
{ 
    numBytes = fileSize;
    numSectors  = divRoundUp(fileSize, SectorSize);
	if (numBytes > 0 && numBytes <= 15872)
	{
    		if (freeMap->NumClear() < numSectors)
		return FALSE;		// not enough space

    		for (int i = 0; i < numSectors; i++)
			dataSectors[i] = freeMap->Find();
    		return TRUE;
	}
	else if (numBytes < 15872 && numBytes <=32000)
	{
		if (freeMap->NumClear() < numSectors)
		return FALSE;		// not enough space

    		for (int i = 0; i < 61; i++)
			dataSectors[i] = freeMap->Find();
    		//return TRUE;
		//indirect pointer
		int* temp = &dataSectors[61];
		temp = new int[64];
		for (int j=0; j<64; j++)
			temp[j] = freeMap->Find();
		return TRUE;
	}
	else if (numBytes > 32000)
	{
		if (freeMap->NumClear() < numSectors)
		return FALSE;		// not enough space

    		for (int i = 0; i < 60; i++)
			dataSectors[i] = freeMap->Find();
    		
		
		//indirect pointer
		int* temp = &dataSectors[60];
		temp = new int[64];
		for (int j=0; j<64; j++)
			temp[j] = freeMap->Find();
		
		//double indirect
		int* temp2 = &dataSectors[61];
		temp2 = new int[64];
		for (int k=0; k<64; k++)
		{
			int* temp3 = &temp2[k];
			for (int l=0; l<64; l++)
			{
				temp3[l] = freeMap->Find();
			}
			return TRUE;
		}
	}
}

//----------------------------------------------------------------------
// FileHeader::Deallocate
// 	De-allocate all the space allocated for data blocks for this file.
//
//	"freeMap" is the bit map of free disk sectors
//----------------------------------------------------------------------

void 
FileHeader::Deallocate(BitMap *freeMap)
{
	if (numBytes > 0 && numBytes <= 15872)
	{
    		for (int i = 0; i < numSectors; i++) {
			ASSERT(freeMap->Test((int) dataSectors[i]));  // ought to be marked!
			freeMap->Clear((int) dataSectors[i]);
		}
	}
	else if (numBytes > 15872 && numBytes <= 32000)
	{
		for (int i = 0; i < 60; i++) {
			ASSERT(freeMap->Test((int) dataSectors[i]));  // ought to be marked!
			freeMap->Clear((int) dataSectors[i]);
			}
		int* temp = &(dataSectors[60]);
		for (int j=0; j<64; j++)
		{
			freeMap->Clear((int) temp[j]);
		}
		delete temp;
	}
	else if (numBytes > 32000)
	{
		for (int i = 0; i < 60; i++) {
			ASSERT(freeMap->Test((int) dataSectors[i]));  // ought to be marked!
			freeMap->Clear((int) dataSectors[i]);
			}
		int* temp = &(dataSectors[60]);
		for (int j=0; j<64; j++)
		{
			freeMap->Clear((int) temp[j]);
			
		}
		int* temp2 = &(dataSectors[61]);
		for (int k=0; k<64; k++)
		{
			int* temp3 = &temp2[k];
			for (int l=0; l<64; l++)
			{
				freeMap->Clear((int) temp3[l]);
			}
		}
		delete [] temp2;
		delete [] temp;

	}
}

//----------------------------------------------------------------------
// FileHeader::FetchFrom
// 	Fetch contents of file header from disk. 
//
//	"sector" is the disk sector containing the file header
//----------------------------------------------------------------------

void
FileHeader::FetchFrom(int sector)
{
    synchDisk->ReadSector(sector, (char *)this);
}

//----------------------------------------------------------------------
// FileHeader::WriteBack
// 	Write the modified contents of the file header back to disk. 
//
//	"sector" is the disk sector to contain the file header
//----------------------------------------------------------------------

void
FileHeader::WriteBack(int sector)
{
    synchDisk->WriteSector(sector, (char *)this); 
}

//----------------------------------------------------------------------
// FileHeader::ByteToSector
// 	Return which disk sector is storing a particular byte within the file.
//      This is essentially a translation from a virtual address (the
//	offset in the file) to a physical address (the sector where the
//	data at the offset is stored).
//
//	"offset" is the location within the file of the byte in question
//----------------------------------------------------------------------

int
FileHeader::ByteToSector(int offset)
{
	if (numBytes > 0 && numBytes <= 15872)
	{
		return(dataSectors[offset / SectorSize]);
	}
	else if(numBytes > 15872 && numBytes <= 32000)
	{
	//search in direct pointers
		if (dataSectors[offset / SectorSize] < 61)
		{
			return(dataSectors[offset / SectorSize]);
		}
	//search using indirect pointer
		else if ((offset / SectorSize) > 60){
			int* temp = &(dataSectors[61]);
			return temp[(offset / SectorSize)-60];
		}
	}
	else if (numBytes > 32000 && numBytes < DiskSize)
	{
		if (dataSectors[offset / SectorSize] < 61)
		{
			return(dataSectors[offset / SectorSize]);
		}
		else if ((offset / SectorSize) > 59 && (offset/SectorSize) < 61){
			int* temp = &(dataSectors[60]);
			return temp[(offset / SectorSize)-60];
		}
		//double indirect pointer
		else if ((offset / SectorSize) > 61)
		{
			int* temp = &(dataSectors[61]);
			int* temp2 = &(temp[(offset/SectorSize)-60]);
			int* temp3 = temp2[(offset/SectorSize)-124];
			return temp3;
		}

	}
	else
	{
		printf("File Size exceeds available disk space. \n");
	}
}

//----------------------------------------------------------------------
// FileHeader::FileLength
// 	Return the number of bytes in the file.
//----------------------------------------------------------------------

int
FileHeader::FileLength()
{
    return numBytes;
}

//----------------------------------------------------------------------
// FileHeader::Print
// 	Print the contents of the file header, and the contents of all
//	the data blocks pointed to by the file header.
//----------------------------------------------------------------------

void
FileHeader::Print()
{
    int i, j, k;
    char *data = new char[SectorSize];

    printf("FileHeader contents.  File size: %d.  File blocks:\n", numBytes);
    for (i = 0; i < numSectors; i++)
	printf("%d ", dataSectors[i]);
    printf("\nFile contents:\n");
    for (i = k = 0; i < numSectors; i++) {
	synchDisk->ReadSector(dataSectors[i], data);
        for (j = 0; (j < SectorSize) && (k < numBytes); j++, k++) {
	    if ('\040' <= data[j] && data[j] <= '\176')   // isprint(data[j])
		printf("%c", data[j]);
            else
		printf("\\%x", (unsigned char)data[j]);
	}
        printf("\n"); 
    }
    delete [] data;
}
